Deep snow is incredibly tiring for dogs and people. There would come a point when our pup would switch from trying to walk to using a bounding motion instead. Presumably this is more efficient but it still looked like really hard work to me.
We got halfway along the route, and I decided to turn back on our back trail so he could walk. He’s so mellow I’m going to start training him in the prospector. He’s not been a canoe dog but I think he’s trainable at 1-1/2 years. He loves snow. Doesn’t pace himself much. He did stick to the trail we cut on the way back.